Honor thy Father by Dream Theater - I swear Portnoy is the best drummer ever.

Edit: Nightwish is awesome btw =p

Epic 20min + song by Dream Theater called Octavarium (this is progressive metal so the mood and tempo/beat and genre changes all the time, slow at the start, faster/heavier at the end in this one), [MEDIA=youtube]xK3qylwd-M0[/MEDIA]

I honestly believe Dream Theater has one of the best keyboardist/guitarist/bassist THE best drummer and the singing well that just depends on what you like :).

(lol lots of edits, but in that video Rudess the keyboarder had a bit of a solo session, so it's a bit longer then normal =p)

The Zoobie Cantata Online
Performed by The Academy of St. Goober in the Streams, Shoezisa Zoobikawa, Music Director, in conjunction with the chorus of The Church Of The Elder Brothers and Sisters of the Secondarily Generalized Ascendent Masters, Twice Removed.

Sorry for the number of songs posted, but that does cover all the songs that I think (at the moment) should be classed as some of the best in their respective areas.

So I won't post anymore...but you may as well give all these a go 'cause you never know ;). I especially recommend Erik Mongraine for Astronuc.

I also highly recommend Devin Townsend to anyone who likes melodic rock. But I will warn you that he has another band called Strapping Young Lad and this won't be your thing unless you like heavy metal. If you're into heavy metal and haven't heard of SYL then I also highly recommend it. But if you only like rock then stick to The Devin Townsend Band songs.